With the rapid development of electronics and communication technologies, mobile application devices, such as cell phone, personal digital assistant, video and audio player (e.g. MP3 or MP4), and hand-held game machine (e.g. the PSP series presented by Sony), with their advantages of light weights and portability, are enjoying general popularity. To expand the size of visual interfaces of mobile application devices, the display screens configured in the mobile application devices are made larger in size. However, the sizes of the mobile application devices themselves limit the expansion of the visual interfaces. In view of this, many existing mobile application devices are provided with only, for example, a four-way control key, while the physical keypad or physical keys are removed, so as to expand the sizes of the display screens. To compensate for the missing of the physical keypad or keys, a virtual keypad or virtual keys may be provided on the display screen.
In addition, online interaction function is becoming a renovation point in the industry of household electronic devices, such as conventional television, home digital player, and digital album. The basic online applications, such as searching, chatting, and web address inputting, are presenting a challenge to the household inputting device that is generally a remote controller at present. Similarly a virtual keypad or virtual keys may be provided on the screen of a household electronic device.
FIG. 1a is a schematic diagram illustrating an interface which displays virtual numerical keys on a display screen according to the existing technologies. As shown in FIG. 1a, the virtual numerical keys include dial keys corresponding to the numbers 1, 2, 3, . . . , 9, and 0, respectively, and a few functional keys. Generally each dial key may correspond to three letters, and the numbers of times of pressing the dial key may determine which one of the three letters should be input. For example, the letter “s” is input if the numerical key “7” is pressed four times. With the method, the inputting of a Chinese character by entering the letters contained in the Chinese phonetic transcription (Pinyin) of the Chinese character becomes very troublesome. The inputting speed depends not only upon the numbers of the letters contained in the Chinese phonetic transcription of each Chinese character and the positions of the letters among the keys. Further, since the keys are virtual keys displayed on the screen, the inputting of characters inevitably involves the switching between the keys that requires the combined usage of a four-way key and a confirming key. For example, if the characters “SONY” are to be inputted by using the above key inputting method, the number of times of pressing the four-way control key and the confirming key will reach 18. Therefore, the inputting method is not only time consuming and laborious, but also inefficient. Moreover, the frequent pressing of the keys may bring about a structural impair to the keys. In addition, the small size of a terminal device, such as a cell phone, inconveniences the operation of the fingers of a user, thereby resulting in the operation fatigue of the user and even some ailments in his/her finger articulations.
FIG. 1b is a schematic diagram illustrating an interface which displays a virtual QWERTY keypad on a display screen according to the existing technologies. As shown in FIG. 1b, the virtual QWERTY keypad is provided with numerical keys 1, 2, 3, . . . , 9, and 0, letter keys A-Z, and symbol keys for other special symbols. As shown in FIG. 1b, a character may be inputted by pressing the confirming key and the key corresponding to the character. However, the virtual keypad requires a four-way control key to enable the switching between the keys. For example, the switching from the letter “A” to the letter “N” needs two pressing actions, i.e. the pressing of the “Right (Left)” key and the pressing of the “Up (Down)” key. Then the letter “N” may be inputted by pressing the confirming key. Taking the inputting of characters “SONY” as an example again, by using the character inputting method as shown in FIG. 1b, the number of times of pressing the keys (including the four-way control key and the confirming key) may be reduced to 11. However, such a method still can not meet the requirements of fast character inputting.
A US patent application, the publication Number of which is 20010026274 A1, discloses an information processing device, a character input method, and computer-readable storage medium storing a program for causing the computer to execute the method. As shown in FIG. 2, the information processing device includes a display screen 102, a four-way controller 106 (including a confirming key), a character type select key 107 and a clear key 108. The display screen 102 consists of an input character display unit 103, a row display unit 104, and a character display unit 105. The device is characterized in that all the possible characters are divided into a plurality of character groups (such as “A”, “Ka”, “Sa”, “Ta”, “Na”, . . . , “Ra”, “Wa”), each character group includes a plurality of characters (for example, the character group “Ta” includes “Ta”, “Ti”, “Tu”, “Te”, and “To”). Any character may be selected and input by pressing the four-way controller 106. Compared with the previously described methods, the method can reduce the number of times of pressing the keys, thereby increasing the efficiency of character inputting.
In the above described patent application, however, the row display unit 104 displays a plurality of character groups and the character display unit 105 displays a plurality of characters in a selected character group. When selecting a character, an operator has to move the curser to the character group containing the character in the row display unit 104 (by using the “Left” and “Right” keys), and then move the cursor to the character to be selected in the plurality of characters displayed in the character display unit 105 (by using the “Up” and “Down” keys), and finally press the confirming key of the four-way controller 106 to confirm the character so that the character is displayed on the input character display unit 103. This inputting process is also rather troublesome. Particularly, the above mentioned steps have to be repeated in the case of an input error or in the case of re-inputting for amendments. Therefore, the efficiency of character inputting in this method also needs improvement.